Letters To The Editor - Mail Truck - September 2008

Sport Truck Letter Of The Month

Vin's DieselI own a very nice, rust-free, '85 Chevy Fleetside shortbed pickup that unfortunately has a bad motor. The 350 V-8 is knocking worse and worse all the time, so it's only a matter of time before it blows. The engine has over 200,000 miles on it, so it's done its time.

My cousin, Vincent, has a '78 Chevy C10 Fleetside longbed that's a total rust bucket. Vinnie's truck has a 350ci diesel engine that still runs OK. Vinnie plans to scrap his truck, and he said I could have the diesel engine for free.

I got to thinking that with all the fuss about fuel economy and gas prices maybe I could convert my truck to diesel. The two trucks are essentially the same and both engines are 350s, so could I either swap the whole diesel engine into my truck or could I take the best parts from both engines and make one good one?Jimmy Spanovia e-mail

You couldn't take a thousand '78-'85 GM 350ci diesels and make a good engine. Oldsmobile developed the engine in your cousin's truck. It was the engine that almost single-handedly set back the cause of diesel engines in America by two decades.

The fact that your cousin's truck still runs is the result of a hole in the cosmos, or maybe it spent more time rusting than being driven. Most of these rolling, knocking smoke bombs self-destructed.

These engines literally destroyed themselves from the inside out. Few owners changed oil as often as recommended and this was critical because of the poor-quality diesel (high water content), the lack of a fuel-tank water separator, and weak head bolts. The water and the diesel's high sulfur content contaminated the oil, which led to internal corrosion. The water in the diesel caused head-gasket failures and, combined with weak head bolts, lots of ruined engines. The poor engines were under attack on all fronts.

The '78 Olds diesels were the worst of a very bad bunch. They took the longest to warm up. A safe warm-up time was one minute. Better glow plugs greatly reduced warm-up times but didn't cure the more destructive problems. Fuel economy wasn't all that great (low 20s), but it was better than contemporary gas engines.

As for engine interchangeability, there isn't any besides the valve covers and water pump. The bore spacing is the same, but the diesel used a heavy-duty block with unique internal components and unique cylinder heads.

Sneak PeekHey guys, I was looking at the Apr. '08 issue and was reading the "Attitude Adjustment" story on Galen's Colorado and noticed that on page 93 the rearend has drum brakes and on page 96 it has disc brakes. Did I miss something in your article, or did you just not mention that? Love your mag. Keep up the good work!Dave Norgordvia e-mail

Nice catch there, Dave. Galen was photographing several articles at the same time, so you spotted the next upgrade, a rear disc-brake conversion. You can read all about that upgrade and how Galen fit 20s on his ride in the May issue of Sport Truck.